Oxymatrine Synergistically Potentiates the Antitumor Effects of Cisplatin in Human Gastric Cancer Cells

Cisplatin (CDDP) has been extensively used for gastric cancer (GC) treatment but limited by drug resistance and severe toxicity. The chemo-sensitizers that enhance its efficiency and overcome its limitation are urgently needed. Oxymatrine (OMT), a primary active ingredient from the dry roots of Sophora favescens, has shown powerful anti-cancer property with little side-effect. In this study, we explored the chemo-sensitization of OMT to potentiate the anti-tumor effect of CDDP. GC cell lines were dealt with OMT and/or CDDP and then subjected to different experimental methods. We found that OMT could significantly potentiate the CDDP-caused BGC-823 and SGC7901 cells viability loss, and OMT acts synergistically with CDDP. The combinative treatment could arrest cell cycle in G0/G1 phase by increasing p21, p27 and decreasing cyclin D1, and induced apoptosis by ROS generation and AKT/ERK inactivation. Inhibition of ROS respectively reversed the cell death induced by OMT and/or CDDP, suggesting the pivotal roles of ROS in the process. Moreover, OMT enhanced the antitumor effects of CDDP in nude mice bearing BGC823 tumor xenografts in vivo. Taken together, this study highlights that the co-treatment with OMT and CDDP exerted synergistic antitumor effects in GC cells, and that these effects may be mediated by ROS generation and inactivation of the AKT/ERK pathways.